This relates to the field of medical devices and more particularly to devices for percutaneous dilation.
Certain medical devices are known that are used in the atraumatic dilation into a patient, such as percutaneously accessing a patient""s air passageway and dilating an opening thereto, and forming an ostomy in the tracheal wall. A tracheal tube is then inserted through the ostomy and into the trachea to establish a passageway for unobstructed air flow. To minimize trauma to the patient, it has been found desirable to initially incise only a small opening as an entrance, and thereafter to enlarge the opening with further dilation.
Sold by Cook Critical Care, Division of Cook Inc., Ellettsville, Ind., is the xe2x80x9cCiaglia Percutaneous Tracheostomy Introducer Setxe2x80x9d, used for controlled percutaneous introduction of tracheostomy tubes. Sequentially sized dilators (from 12 french to 38 french) are advanced over a wire guide/guiding catheter system to facilitate gradual dilation of the tracheal entrance site to an appropriate size; one such dilator is shown in FIG. 1 and herein below described. The tracheostomy tube is placed by fitting the tube over the appropriate size dilator and advancing the tube into position. Each of the dilators includes an elongated linear shaft for manual gripping and manipulation, and is provided with a curved distal end concluding in a tapered tip that in use is coated with lubricating jelly, all to minimize trauma. First, the smallest dilator (12 french outer diameter) is first selected and placed over a guiding catheter and guide wire that extend through the opening until the tip is adjacent to the opening. Then the tapered tip is urged gently into the percutaneous incision and between adjacent ones of the trachea rings, and is gently withdrawn and reinserted to gradually widen the opening. The first dilator is then withdrawn and removed, and replaced by the next larger sized dilator and the procedure is repeated until the appropriate sized ostomy has been created.
It is desired to simplify the procedure used to create the ostomy and to shorten the length of time involved in its creation.
The present invention is directed toward a single dilator that is used to define the ostomy in one pass, thus replacing the several sequentially sized dilators and eliminating the repeated changing thereof, and thereby greatly simplifying the procedure and substantially shorten the time to define the ostomy, all serving to minimize patient trauma. The single dilator includes a soft, pliant tapered tip identical in shape and size and in tip inner diameter to those of the prior art dilators, and additionally includes a curved distal portion extending from the tapered tip toward the proximal end, and the generally linear shaft. The curved distal portion is tapered to extend from a diameter of 12 french (for example) adjacent the tapered tip, to a diameter of 38 french adjacent the linear shaft. Preferably both the curvature and the taper of the curved tapered distal portion from the distal tip to the shaft is gradual with no discontinuities. Also preferably, the curved tapered distal portion has a gradual transition in flexibility from very flexible at the short distal tip portion to generally rigid at the generally linear shaft portion, such as by gradually changing its wall thickness.
The resultant shape of the dilator of the present invention can be said to resemble the horn of a rhinoceros. Particularly useful for tracheostomies, the continuing curve of the distal end portion enables the increasingly longer inserted portion of the dilator to be situated in the trachea thus facilitating clearing the posterior tracheal wall.
Preferably the curved tapered distal portion and the short distal tip portion are provided with a hydrophilic coating that obviates the need for lubricating jelly and provides a very low coefficient of friction when hydrated, thus facilitating insertion into and withdrawal from the tracheal opening.
An embodiment of the invention will now be described by way of example with reference to the accompanying drawings.